What is Depth Of Field bracketing?

Question

I understand the concept of (auto-)bracketing, in general. And I understand that exposure bracketing is used for HDR and focus bracketing is used for focus stacking. But I am unable to imagine what DOF bracketing is or what its use could be. Any pointers?

Answer 1

DoF bracketing is essentially the same as focus bracketing, but rather than change the focus point/plane for each shot, you change the aperture to vary the depth of field.

Imagine you are taking a shot of, say, a cluster of cherry blossoms. You want the background blurred so you open the aperture right up. But this means only part of the cluster is in focus. So you stop down the aperture a little, which gives you deeper DoF, so more of the flowers are in focus, and so on.

Once you've got the shots you need to get the entire cluster in focus, you can put them all together in post - sharp flower cluster and blurred background. Bracketing in small increments means you can get a nice transition between the fore and backgrounds. If you just took one at f/2.8 and another at f/16 it would be tricky to get a natural looking result.

Answer 2

Depth Of Field bracketing is performed by taking several shots of same scene with different aperture (compensating change in exposure by adjusting ISO, shutter speed or lighting power).

Bracketed images are then used to have a wider selection of images to select the one with most appropriate depth of field in post. Or you could use masking and combine background from wide aperture shot with subject from tight aperture shot.

Answer 3

So you know, what "bracketing" means in general... taking a series of shots other than the one you or the meter have chosen.

Exposure bracketing is the most common. Right. It is done by the photographer or automatically by the camera, by taking an exposure at the suggested speed, aperture and ISO settings, and then one or more exposures using a different speed, aperture or ISO setting -- but always only one of these.

DoF bracketing is less common because DoF can be considered part of the composition and is a matter of artistic interpretation, something better left to the photographer rather than the camera. Like exposure bracketing, it can be done by the photographer or the camera (assuming your camera has DoF bracketing). But DoF bracketing is done by taking one exposure at the suggested speed, aperture and ISO settings, and then one or more exposures using a different aperture and a complimentary change in speed or ISO setting to compensate for the change in aperture. So, two settings are changed not just one.

If you can't think of a reason to use DoF bracketing, try to come up for a reason to use either speed or ISO bracketing in general use.

In the case of Canon cameras, however, there was once a function called DoF bracketing that allowed the photographer to focus on the nearest point they wanted in focus, take a reading by partially depressing the trigger, and then a second reading at the furthest point they wanted in focus and taking a second reading. This locked in that focus range by setting the aperture automatically and allowed the photographer to the photographer or program mode to modify the other two settings as needed to keep the focus. I haven't owned a Canon or worked at a camera shop since Moses so I'm not sure if Canon still uses that terminology.

Answer 4

I do depth of field bracketing a lot. I shoot at different apertures to see what background I like best.

On the K-5, it's not that hard to use exposure bracketing as depth of field bracketing when using RAW. It's close to an ISOless sensor due to it's dark read noise— it's digital gain performance performance is near equivalent to it's analog amplifier gain. On other sensors, you will get somewhat higher noise at the smaller apertures than manually doing it. Here are the steps:

• Set the camera to take the overexposed shot first
• Go to shutter priority and turn auto ISO off
• Set exposure bracketing. Calculate what X.X EV stepsize and number of shots you want to get the apertures you want (too much and you'll hit f/22, which is a bit worthless)
• Use -EV compensation so the overexposed shot is at 0 EV, to not clip highlights
• Set your shutter to what you're comfortable with regards to motion blur and camera shake, if applicable
• Set your ISO such that your aperture is the widest that you want
• Shoot your images
• In post, set each shot +X.X EV (or use auto tone in lightroom)